Two minute slope inhalation technique for cerebral blood flow measurement in man. 1. Method.

The two minute slope method of measuring cerebral blood flow (CBF) by inhalation of 133Xe is described. It requires the subject to remain still for only two minutes and is thus applicable to a wide variety of patients and to investigations involving brief physiological stimuli. The influence of extracerebral blood flow on CBF calculated by this method has been studied. Results from the two minute slope inhalation method using two minutes of data correlate well with those obtained by carotid injection using either two minutes or 10 minutes of data.